1. Field of the Invention
The present invention relates to devices used in lifting and holding a bulky item, such as a cabinet or a ceiling frame, in proper position during installation of the item. In particular, the invention relates to a lifting device that can be used by an installer to lift, position and install and item such as a heavy, bulky, kitchen cabinet without requiring the help of a second person.
2. State of the Art
Normally, when installing an item such as a cabinet or ceiling frame, it is necessary for a helper to lift the cabinet in place against a wall or ceiling while the item is secured to the wall or ceiling by the installer. The use of a helper increases the labor cost of such installation. It would be highly desirable to provide apparatus that can be safely operated by one person to lift and hold a cabinet in place while that person secures the cabinet to the wall or ceiling.
The use of apparatus to lift heavy items is, of course, known in the prior art. U.S. Pat. Nos. 1,725,329; 3,365,080; and 4,027,802 disclose apparatus for lifting ceiling frames. While these devices disclose hoists for lifting ceiling frames, they do not disclose or suggest devices which are suitable for installing cabinets. U.S. Pat. No. 1,725,329 discloses a device for raising a platform, but there is no suggestion that the platform could be used for lifting and holding cabinets or ceiling frames in place while the cabinets or ceiling frames are being installed to the wall or ceiling.
U.S. Pat. Nos. 4,715,760; 4,955,592; and 5,322,403 disclosed apparatus that can be used in lifting cabinets and the like during installation to a wall or ceiling. Each of the devices of these patents utilizes a single support shaft extending upwardly from a base member to support the cabinet. The cabinet must be precariously balanced on the upper end of the single support shaft. The device of U.S. Pat. No. 4,715,760 has a small platform at the top of the support shaft upon which the cabinet is placed; however, the small platform provides only minimal stabilization for the cabinet as it is being lifted. The cabinet must be carefully balanced and steadied during the lifting operation. U.S. Pat. No. 4,955,592 utilizes a larger platform at the upper end of the lift shaft, but the cabinet must still be carefully balanced and steadied during the lifting operation to prevent unsafe tilting of the cabinet.
U.S. Pat. No. 5,322,403 utilizes a tripod that supports the lift shaft intermediate its top and bottom ends. The lift shaft has a massive counterweight that extends to the floor, and the portion of the lift shaft that extends below the top of the tripod is connected rigidly with the bottom of the legs of the tripod. This arrangement stabilizes the lift shaft against unsafe tilting, but the apparatus itself becomes bulky and hard to use.